Modelling of the subgrid scale wrinkling factor for large eddy simulation of turbulent premixed combustion

Abstract

We propose a model for assessing the unresolved wrinkling factor in the large eddy simulation of turbulent premixed combustion. It relies essentially on a power-law dependence of the wrinkling factor on the filter size and an original expression for the ‘active’ corrugating strain rate. The latter is written as the turbulent strain multiplied by an efficiency function that accounts for viscous effects and the kinematic constraint of Peters. This yields functional expressions for the fractal dimension and the inner cut-off length scale, the latter being (i) filter-size independent and (ii) consistent with the Damköhler asymptotic behaviours at both large and small Karlovitz numbers. A new expression for the wrinkling factor that incorporates finite Reynolds number effects is further proposed. Finally, the model is successfully assessed on an experimental filtered database.

Keywords:

• large eddy simulation
• efficiency function
• flame wrinkling
• strain
• stretch

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Erratum

Acknowledgements

Denis Veynante from laboratory EM2C, Chatenay-Malabry, is gratefully acknowledged for fruitful discussions about an earlier version of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support from Agence National de la Recherche under project IDYLLE is gratefully acknowledged. We are also thankful to the CNRS, the University of Orléans, and the French Government Program ‘Investissements d'avenir’ through the LABEX CAPRYSSES.